Filler loaded elastomeric compositions having improved extrudability and physical properties

ABSTRACT

An elastomeric composition containing (a) an Alpha olefin/nonconjugated diene copolymer, (b) a clay or carbon black filler and (c) a surfactant. The surfactant improves both the extrudability and vulcanizate properties of the copolymer.

United States Patent Thomas Joseph Kealy;

William John Keller, both of Wilmington, Del.

[21] Appl. No. 787,250

[22] Filed Dec. 26, 1968 [45] Patented Dec. 14, 1971 73] Assignee E. I. du Pont de Nemours and Company Wilmington, Del.

[72] Inventors [54] FILLER LOADED ELASTOMERIC COMPOSITIONS HAVING IMPROVED EX'IRUDABILITY AND PHYSICAL PROPERTIES 11/1966 Keller et al.

3,288,709 252/875 3,361,691 1/1968 Mazzeo 260/23.5 3,408,320 10/1968 Brucksch 260/215 FOREIGN PATENTS 2/1968 GreatBritain 4/1967 Canada OTHER REFERENCES Condensed Chem. Dictionary (7th ed.) Reinhold NY. (1966) page 531QD5c5 Waddell et al. Rubber Age 94, 427- 428 and 435 (1963) Du Pont Publication TML-l (1962) Tordella SPE Journal, Feb. 1956, page 36.

Du Pont Development Products Report No. 18, ECD-330, A Sulfur-Curable Ethylene-Propylene Elastomer. Dec. 1961, pages 3- 6.

Primary Examiner-Morris Liebman Assistant ExaminerH. H. Fletcher Attorney-Vernon R. Rice ABSTRACT: An elastomeric composition containing (a) an a-olefin/nonconjugated diene copolymer, (b) a clay or carbon black filler and (c) a surfactant. The surfactant improves both the extrudability and vulcanizate properties of the copolymer.

FILLER LOADED ELASTOMERIC COMPOSITIONS HAVING IMPROVED EXTRUDABILITY AND PHYSICAL PROPERTIES BACKGROUND OF THE INVENTION Chain-saturated hydrocarbon copolymers of a-olefins are of great importance today for use in a wide variety of elastomeric articles. For many applications such as wire and cable coatings and shoe soles and heels,'these copolymers are loaded with mineral, i.e., nonblack fillers prior to cure. For other applications such as brake diaphragms it is desirable to extend the aolefin copolymer with'a reinforcing carbon black. Improvements in processing and curing of both mineral and carbon black loaded stocks is a continuing objective. Improvements in extrusion rate and in vulcanizate properties such as compression set and tensile strength are particularly desirable.

It is known that some shortcomings in the properties of aolefin hydrocarbon copolymer vulcanizates can be overcome if the filled stocks are specially heat treated prior to incorporation of the curing agent. This heat treatment is more effective if certain promoters are present during the heat-treatment such as dinitroso-, dioximeand aromatic quinoid compounds. It is, however, quite inconvenient and expensive to carry out the heat treatment process. The extra time required to cool the heat-treated stocksbefore the curing agent can be added considerably lowers the production rate.

There is a need in the art,therefore, to improve the extrudability and vulcanizate properties of filler-loaded a-olefin/nonconjugated diene elastomeric stocks.

SUMMARY OF THE INVENTION This invention provides a filler-loaded elastomer consisting essentially of (a) an elastomeric copolymer of at least one amonoolefin and at least one nonconjugated hydrocarbon diene, said copolymer having about 0.1-2.0 gram moles of ethylenic unsaturation per kilogram of copolymer (b) about 20-300 parts by weight per 100 parts of copolymer of a filler, and (c) about 0. l-6.0 parts by weight of an interfacially active compound per lparts of copolymer. Addition of interfacially active compounds (surfactants) to filler-loaded elastomeric stocks according to this invention improvesthe extrudability of the copolymer stock and the tensile strength and compression set of its vulcanizates.

DETAILED DESCRIPTION The elastomeric copolymers used in this invention are those made from at least one a monoolefir and at leastone nonconjugated diene. The a-monoolefins have the structure RCl-I=CH where R isliydi'ogen or CI CL alkyl, preferably straight chained. V Representativc 1995 9 991? re propylene, ethylene, l-bu t erie, l penten l-hexene, l-heptene, l-octene, l-octadecene, 6-ethyll-decene and S-methyll-hexene.

The nonconjugated dienes useful in this invention can be open-chain or cyclic compounds. Preferably, only one of the 1 V wherein Z,is C,-C alkylene and Z Z and Z, are independently hydrogen or an alkyl radical, with the proviso that the 2 groups indicated in said formula are selected such that the diene has from about six-22carbon atoms. Representative dienes are l,4-hexadiene; 1,9-octadecadiene; 6-methyl-1,5- heptadiene; 7-methyl- 1 ,6-octadiene; l 1-ethyl-l,l ltridecadiene; 9-ethyll ,9-undecadiene; 7-ethyll ,7-

nonadiene; 8-propyl-1,8-undecadiene; 8-ethyl- 1,8-decadiene; IO-ethyll ,9-dodecadiene; l2-ethyl-l l 2-tetradecadiene; l3- n-butyl-l l Z-heptadecadiene; and l-ethyll l 5-heptadecadiene. Open-chain dienes having two terminal nonconjugated carbon-to-carbon double bonds, where Z Z, and Z, are hydrogen, e.g., 1,5-hexadiene or 1,4-pentadiene, can be used but are much less preferred. Cyclic nonconjugated dienes include dicyclopentadiene, S-aIkenyI-substituted-Z- norbomenes, e.g., 5-butenyl-2-norbornene, S-aIkylidene-Z- norborenens (including ethylidene-Z-norbornenes and 5- methylene-2-norbomene), 2-alkyl-2,5-norbornadienes, (e.g., 2-ethyl-2,5-norbomadiene) and 1,5-cycloctadiene. The preferred diene is 1,4-hexadiene because of the outstanding physical properties of the copolymers prepared therefrom.

Representative copolymers made from the above-described a-monoolefins and nonconjugated dienes and methods for their preparation are given in U.S. Pat. Nos. 2,933,480; 3,000,866; 3,063,973; 3,093,620; 3,093,621; 3,151,173; 3,260,708; and Belgian Pat. No. 697,049. Particularly preferred because of their excellent physical properties are copolymers of from about 30 to weight percent ethylene, 60 to 20 weight percent propylene, and up to about 10 weight percent 1,4-hexadiene or S-ethylidene-Z-norbomene. The copolymers contain from about 0.1-2.0 and preferably about 0.2-1 .Ogram moles of ethylenic unsaturation per kilogram of copolymer.

In preparing the compositions of this invention, the copolymers described above are compounded with a filler which can be a mineral (nonblack) filler, carbon black or mixtures thereof. A wide variety of mineral fillers or mixtures 697,049. can be employed in the present invention. Representative examples include: kaolin clay, calcined kaolin clay, magnesium silicate, blance fixe, whiting, silica and talc. Kaolin clay and calcined kaolin clay are particularly suitable. Any kaolin clay which is conventionally used for reinforcing elastomers can be employed to make the mixtures of the present invention. In general, these clays have particle sizes in the range of 2 microns. The finer the particle size, the better the filler responds in giving an improved vulcanizate.

The principal physical characteristics of the clays which are preferred for use in the present invention are: (l) a specific gravity of about 2.6; (2) a 325-mesh screen residue below about 3.5 percent, preferably below about 0.35 percent; (3) absorbed moisture content not about about 1 percent; (4) a particle size distribution wherein at least about 55 percent by weight of the particles are two microns or less in diameter; and (5) a pH (in water) of about 4.4 to 7, although specially prepared and treated clays may show pH values of 8 or higher.

The particularly valuable mineral filler is Kaolin clay. Both the hard and the soft" types can be used; however, the hard clays are preferred. Those skilled in the art readily understand that kaolin clays may have identical crystalline structures, yet differ markedly in their ability to reinforce an elastomer stock. The difference in their reinforcing properties appears to depend upon the difference in their particle size distribution. Those skilled in the art will recognize that a hard clay is one which will noticeably reinforce an elastomer stock as reflected by the values of vulcanizate properties such as the modulus at 300 percent extension. In the case of the hard clays a very high proportion, for example about 90 percent, of the particles are smaller than 2 microns; in contrast, only about 60-70 percent of soft clay particles are less than 2 -microns. Commercially available hard kaolin clays include:

Champion Clay," Crown Clay," Harwick No. 1," Suprex Clay; soft kaolins include: Alumex R, Hi-White R, "Mc- Namee Clay," Paragon Clay" and Polyfil F."

Additional information on mineral fillers which is useful in carrying out this invention can be found in U.S. Pat. No. 3,355,417 to Martin and Reinforcement of Elastomers," Edited by G. Kraus, Interscience Publishers, J. Wiley & Sons, Inc., N.Y., 1965.

When carbon black is the tiller used, channel and furnace process blacks are preferred. SAF furnace black is an excellent reinforcing agent; other furnace blacks such as SRF, I-IMF, CF, IMF, and FF are satisfactory. Stocks containing channel blacks are slightly slower curing; however, any of them, e.g., EPC, MPC, HPC, CC can be used. Thermal carbons can be employed but provide a lower order of reinforcement.

The mineral fillers are used in the amount of about 20-300 parts per 100 parts of copolymer. When kaolin clay is the filler, the amounts are preferably in the range of 80-200 parts. Carbon black is used in the amounts of about 20-150 parts and preferably 30 to 80 parts per 100 parts of copolymer.

The surfactants used in this invention are selected classes of the cationic, anionic and nonionic types. Representative cationic surfactants correspond to the formula wherein R is a long chain alkyl, alkaryl or aralkyl group having from eight to 22 carbon atoms; R, and R taken individually are C -C alkyl and taken together with the nitrogen atom can form a five or six membered aliphatic or aromatic ring consisting of carbon atoms and not more than two hetero atoms, including the nitrogen atom shown, from the group of nitrogen and oxygen; R is C,C alkyl or benzyl and X is halide, nitrate, methanosulfate (Cl-[ 0809 or ethanosulfate (CH -CH,OSO Examples of suitable cationic surfactants covered by this formula are: cetyl trimethyl ammonium chloride, stearyl dimethyl benzyl ammonium chloride, cetyl dimethyl ethyl ammonium bromide, cetyl dimethyl benzyl ammonium chloride, dodecyl trimethyl ammonium chloride, distearyl dimethyl ammonium chloride, N-cetyl-N-ethyl morpholinium ethanosulfate, N-dodecyl benzyl-N,N,N- trimethyl ammonium chloride, lauryl pyridinium chloride, lauryl isoquinolinium bromide, and stearyl trimethyl ammonium chloride. Another cationic surfactant not covered by the above formula is stearamido propyl dimethyl B-hydroxyethyl ammonium nitrate.

Representative anionic surfactants are alkali metal or ammonium sulfates, the anion of which has the formula R,OSO,,-wherein R, is C r-C alkyl or alkenyl; alkali metal or ammonium sulfonates, the anion of which has the formula R SQ wherein R5 is C -C alkyl, c3 C20 Ol' Cg C 20 aralkyl in which the aryl groups have six to carbon atoms; alkali metal or ammonium phosphates, the anion of which has the formula R OPO -wherein R is the same as R,, defined above; and alkali metal or ammonium phosphonates, the anion of which has the formula R-,PO -wherein R is the same as R, defined above. In the anionic surfactants described herein, the ammonium ion has the formula I IH Q2. at

wherein 0. Q1 and Q, are independently hydrogen, methyl, ethyl or hydroxy ethyl. Examples of anionic surfactants which correspond to the descriptions given above are sodium cetyl sulfate, sodium decyl sulfate, ammonium lauryl sulfate, potassium lauryl sulfate, oleyl sodium sulfate, sodium tetrahydronaphthalene sulfonate, polymethylene bisnaphthalene sodium sulfonate, ammonium undecylbenzene sulfonate, dodccylbenzene sodium sulfonate, dodecylbenzene triethanolamine sulfonate, potassium dodecyl phosphate, sodium lauryl phosphate, sodium dodecylbenzyl phosphonate and potassium cetyl phosphonate.

Other anionic surfactants not included by the above description are: the ammonium salt of monoethyl phenyl phenol monosulfonate, sodium oleyl p-anisidene sulfonate, lauryl picolinium p-toluene sulfonate, sodium salt of sulfonated propyl oleate, synthetic petroleum sulfonate (water cut, molecular weight 320); monobutyl biphenyl sodium monosulfate and the sodium salt of sulfated propyl oleate.

The nonionic surfactants include fatty alkylol amide condensates of the formula wherein R is C -C alkyl, alkaryl, alkenyl or aralkyl and Y and Y' are individually hydrogen or C -C alkanol, with the proviso that not more than one of Y or Y is hydrogen. Examples of such surfactants are hydroxyethyl stearamide, lauryl diethanolamide, myrisu'c diethanolamide, stearic diethanolamide, and lauryl isopropanolamide.

Another important class of nonionic surfactants useful in this invention has the formula wherein Rq=R and Y is a monovalent radical derived from an aliphatic polyhydroxy compound having a molecular weight less than 250, such as sorbitol, pentaerythritol, glucose, propylene glycol and glycerine. Examples of these surfactants are sorbitan monopalmitate, propylene glycol monostearate, glyceryl monostearate, sorbitan monooleate, myristyl lactate, diethylene glycol monostearate and propylene glycol laurate. Other nonionic surfactants include mannide monooleate and sorbide dioleate.

Many of the surfactants described above are present in mixtures which contain complex unidentified materials usually obtained from natural sources. The properties of these materials are well known to those skilled in the art. Such mixtures can also be used in this invention.

The preferred surfactants are sorbitan monopalmitate, lauric diethanolamide and stearyl trimethylammonium chloride because of their special effectiveness in improving the extrudability of the copolymers and the physical properties of their vulcanizates.

The surfactants described above are added to the copolymer stock in the amount of about 0.1-6.0 parts per parts of copolymer. The preferred quantity of surfactant is about 2-4 parts per 100 parts of copolymer since the advantages described herein are generally achieved at these concentrations. The surfactant .can be added before, during or after the addition of other compounding agents. It should be thoroughly mixed with the copolymer, for example, by milling.

The elastomeric compositions of this invention can be readily cured with sulfur, peroxides, phenolic resins or radiation by conventional techniques to give outstanding vulcanizates. In curing with sulfur any of the procedures familiar to those skilled in the processing of natural rubber, butadiene/styrene rubber, butyl rubber and a-olefin/nonconjugated diene rubber, are suitable. It is preferable to use a combination of sulfur, a metal oxide, and a vulcanization accelerator. In general, about 0.2 to 3.5 parts of sulfur are used per 100 parts by weight of copolymer, although it is to be understood that larger or smaller concentrations can be used when deemed desirable. Further information regarding the sulfur curing a-olefin/nonconjugated diene copolymers appears in U.S. Pat. No. 3,865,418.

Detailed information on various types of cures applicable to this invention are: Phenolic resins cures -U.S. Pat. No. 3,287,440 and British Pat. No. 1,125,547; Peroxide cures U.S. Pat. No. 3,033,835; Netherlands Pat. Publication No. 6,613,608 and British Pat. No. 1,120,352; Radiation cures are discussed in Rubber Age 77, Sept. 1955; and two applicable general references on the curing of rubbers are vulcanization of Elastomers," G. Alliger and I, J. Sjothun, Rheinhold Pub. Corp, N.Y. (1964) and vulcanization and Vulcanizing Agents, W. Hofmann, Palmcrton Pub. Co., NY. (i965).

In addition to the interfacially active compound, filler, and curing system, the copolymer can be compounded with other conventional additives such as antioxidants, pigments, petroleum oils and the like. These additives can be introduced at any time prior to extrusion or before the cure begins. The presence of curatives does not affect the extrusion behavior. When shaped articles are made by extrusion, e.g., hose or coated wire, the curatives are added before extrusion (unless a radiation cure is employed).

The compounding can be carried out in conventional equipment such as rubber roll mills or internal mixers of the Banbury type. After the copolymer is banded on the mill, all remaining components can be added in any order except the curing agent which is added last. For processing convenience, the tiller is often added simultaneously with petroleum oil. When internal mixers are employed which rapidly disperse the components and generate enough heat to raise the temperature to about l80-200 F. all compounding components including the surfactants can be added practically simultaneously.

The cure time and temperature needed for optimum results for a particular operation can be routinely determined by those skilled in the art. At curing temperature of about 320 F., representative cure times range from about 5-30 minutes with about -20 minutes being preferred. The more difficulty cured compositions such as the hard clay extended stocks may require at least 20 minutes. Higher or lower temperatures than that indicated above can be employed, e.g., 300 F. and 360 F.

Addition of an interfacially active compound to clay-loaded copolymers according to this invention significantly increases the compounded polymer extrusion rate and improves compression set over cured stocks which are identical except the surfactant is not present. The extrusion rates are increased without a corresponding increase in die swell. The same advantages are realized with carbon black loaded stocks except the compression set is not necessarily improved by addition of the surfactant. These and other aspects of the invention are further illustrated by the examples which follow. The following procedures are used in carrying out the examples.

BANBURY MIXING PROCEDURES A. Compounds for examples l-6 are mixed in a midget" Banbury mixer supplied by the Farrel Corporation of Ansonia, Connecticut. This equipment is described on page 16 of Farrel Corporation's bulletin number 2078, issued in 1964. The mixer has a 340-c.c. capacity. Unless otherwise indicated the actual mixing is accomplished by first adding the polymer to the mixer at a temperature of 90 F. and rotating the blades at 72 rpm. for 30 seconds. At this time, one half of the filler (containing half .of the surfactant used) is added and mixing continued for an additional minute. Then, except for sulfur and accelerators, all remaining ingredients (including the remaining half of the filler containing half of the surfactant) are added and mixed for 4 minutes longer. During the last 3 minutes of the mixing, the speed of the blades is increased to 120 rpm. At the end of the mixing cycle of 6 minutes total, the blades are stopped and the compounded stock removed from the mixer and sheeted off of a conventional rubber mill.

B. The compound of example 7 is mixed in a Farrel Banbury mixer, size OOC," having a chamber capacitor of 263 cubic inches. The mixing is allowed to continue until a temperature of 250 F. is reached at which time the charge is removed and sheeted ofi a rubber mill.

MILL MIXING PROCEDURE In all cases, the curing agents are omitted from the extrusion stock. To illustrate curing behavior, these curing agents are.

Screw Type CURING PROCEDURE EXTRUSION PROCEDURE A. For examples l-6 a commercial two-inch Royle No. l extruder is used together with a Royle three-zone Temp. Control Panel Board under the following general conditions (See John Royle & Sons Bulletin No. 463).

Rubber (Royle AY 000298) PlasticJRoyle AY 00038!) Screw Working Length. 22 e iiiic hes Screw Speed w I "a npirn.

Screw, F. 75or 167 (as described in Examples) Die Orifice 0.l2$ inch (rod) Die, F. 2 l 2 Head Temp. zone 1, F. 2l2

Barrel Temp. zone 2, F. l 6 9 12am: 3. F. l 140 e s t k. 5 75 :19

The stock is fed by hand in strips about l k inch wide and one quarterinch thick. The extrudate is measured in terms of length vs. time and weight vs. length by taking cuts of mm 30 seconds duration over a period of from 1 to 3 minutes. From these measurements the maximum length rate (ft/min.) and the die swell at the maximum rate are determined. Die swell is defined in terms of the percent increase in cross section (area) observed for the extrudate vs. the cross section (area) of the die through which it is extruded. This is determined using the specific gravity of the compound and comparing the weight of a unit length of extrudate to the theoretical weight of a volume of the compound of unit length having the cross section of the die.

B. The stock of example 7 is extruded as a rod using a 1 inch Royle extruder under the following conditions:

Barrel Temp. 270' F.

Die Head Temp. 270 F.

Screw Temp. F.

Screw Speed 35r.p.m.

Die .r-inch I.D. (circular), steel Feed strip V4 inch X2 inch TEST PROCEDURES FOR SAMPLES The following procedures are used:

Mooney Viscosity ASTM D-l646-67 Stress-Strain ASTM D-4l2-66 M Modulus at 100%.extension (p.s.i.)

M, Modulus at 300% extension (p.s.i.)

T, I Tensile strength at break (p.a.i.)

E, I Elongation at break ('k) Compression Set Shore A Hardness Permanent Set atBreak ASTM D39567 (Method B) ASTMD:22l!1-64T ASTM D-4l2-66 (Section 5.5 modified by use ofa 5-minute hold time) The following materials are used in the examples:

EPH COPOLYMER A 44 percent propylene units, and 3.5 percent total 1,4-hexadiene units by weight; there is about 0.33 gram-mole of sulfur-curable unsaturation per kilogram, EPH Copolymer A has an inherent viscosity of about 4.0 (measured at 30 C. on a solution of 0.1 gram of copolymer in 100 milliliters of tetrachloroethylene); the Mooney viscosity (ML 4/250 F.) is about 70.

EPH COPOLYMER B EPl-l COPOLYMER C A copolymer made by copolymerizing ethylene, propylene, and 1,4-hexadiene in tetrachloroethylene in the presence of a catalyst made in situ by combining VCl and diisobutylaluminum monochloride in accordance with U.S. Pat. No. 2,933,480.

The copolymer contains 53.7 percent by weight ethylene, 42 percent by weight propylene and 4.3 percent by weight hexadiene. The ethylenic unsaturation is about 0.4 gmoles/kilogram of polymer; Mooney Viscosity (ML-4/250 F.) is 18.

HARD KAOLlN CLAY The hard kaolin clay (Suprex") is an air-floated type containing 44-46 percent silica, 37.5 39.5 percent alumina, l.52 percent iron oxide, and l-2 percent titanium dioxide by weight. The moisture content (maximum) is 1.0 percent by weight. The pH in water is 4.55.5. This clay has a specific gravity of 2.60, a 325-mesh screen residue ofO. 17 percent (by weight), and the following particle size distribution (by weight): y, 0.1 percent; 5-10u, 28 percent; 4-5p., 1.5 percent; 3-4;.t, 2.3 percent; 2-3p., 3.4 percent; 12,u,9.0 percent; 0.5-1,119.0 percent; ,1. 0.S,u.,61.9 percent.

PARAFFINIC OIL B Paraffinic oil B has a flash point (COC) of 495 F., a molecular weight of 530, and a viscosity gravity constant of 0.803; the SUS viscosities at 100 [210 F. are 508/64.3.

SOFT KAOLIN CLAY The soft Kaolin Clay (*Whitex) has a specific gravity of 2.5 and a pH (in water) of 6.2; about 55 percent of the particles are less than 2 microns in diameter.

CHLOROSULFONATED POLYETHYLENE The chlorosulfonated polyethylene (Hypalon) has a Mooney viscosity (ML-4/2l2 F.) of 30 and analyzes for 29 weight percent C1 and 1.4 weight percent S.

PARAFFlNlC OIL A This paraffinic oil has a flash point (COC) of 595 F., a molecular weight of 820, and a viscosity gravity constant of 0.796; the SUS viscosities at 100/210F. are 2907/165.

COPOLYMER D A copolymer made by copolymerizing ethylene, propylene and 5-ethylidene-Z-norbornene in hexane using a vanadium coordination catalyst according to general directions given in U.S. Pat. No. 3,341,503. The copolymer contains about 50.8

percent by weight ethylene, 45 percent by weight propylene and 4.2 percent by weight diene. The Mooney viscosity is 54.

Throughout the examples, as mentioned above, the extrusion data indicated is obtained on compounds which do not contain the curing system. Addition of the curing system to the copolymer does not significantly affect its extrudability. The samples which contain no surfactant are outside the scope of the invention.

EXAMPLE 1 An ethylene-propylene- 1 ,4-hexadiene tripolymer is compounded as indicated above in the following recipe:

Parts EPH Copolymer A 1.0 Stearic Acid 30 FEF Carbon Black 125 Hard Kaolin clay (Suprex) 4O Paraffinic Oil A Sorbitan surfactant shown in Table 1) Two samples are extruded as described above using a chrome plated steel screw designed for plastics (screw temp.

167 F.) to give the results shown in table 1.

TABLE 1 Sorbitan Max. Extrusion Monopalmilate Rate ft./min. 7! Die Swell '1 part ofantioxidam also present [Polygard tri(rnixed monoand di-nonylphenyl) phosphile] For vulcanization the following ingredients in the amounts indicated (based on 100 parts by weight of polymer) are added to the extrudates on a mill and the compound is cured in a press at 320 F. for 30 minutes: 2 sulfur, 0.5 mercaptobenzothiazole, 1 zinc dimethyldithiocarbamate, 5 zinc oxide. Vulcanizate properties are given in table 11 TABLE II.--VULCANIZATE PROPE RTIES Compression Sorbitan Hardset, 22 hrs./ monopalmitate M M TB E B ness EXAMPLE 2 Example 1 is repeated using EPH Copolymer Bin place of EPH Copolymer A; all other conditions being the same, except no phosphite antioxidant is added. The results are shown in table 111.

TABLE IIL-EXTRUSION AND VULCANIZATE CHARACTE RISTICS Extrusion Percent Percent Sorbitan monorate, die perm. palmitate ft./min. swell M Mano TB EB set EXAM PLE 3 Example 2 is repeated using EPH Copolymer B in a different compound cured for 40 minutes at 320 F. A chrome plated steel screw designed for rubber is used in the extruder, EXAMPLE but other conditions are the same. The compound recipe is as in the previous 4 examples, the interfacially active comfollows. Table IV gives the data obtained; I pound is added to the polymer prior to compounding. in this example a comparison is made between adding the surfactant EPI-l Copolymer s 95 5' to the polymer and adding it to the compound along with the Chlorosulfnnated Polyethylene 5 (Hypalon 40 u zinc oxide 5 fi er Thepolymer type, compound recipe, screw type and steam: Add l cure conditions are the same as in example 4. Results are Hard Kaolin Clay 12s (Suprex Clay) shown In a l 1 Soft Kaolin Clay 75 (Whitex Clay) Parai'finic on a 70 (Sum I50) EXAMPLE 6 sum" 2 This example is a repeat of example'4 except the polymer is Z-Mercaptobenzolhiazole 1.5 (MBT) Copolymer D and the screw temperature is reduced to 75 g z ly t h i ifid md 3-: (l'hiuram M) F. The interfacially active material is added to the filler during en met y ene iuram exuu e etrone A) Tenufium dmhyldithiocarbmm M (mime) compounding. A cure time of IS minutes is included in this exsmbimn Monopalmime (As shown" 15 ample for comparison with the longer cure times normally iv) u ed TABLE IV.VULCANIZATE PROPERTIES Maximum Compresoxtrusion Percent sion set, Sorbitan rate, it./ die Hard- 22 hrs. palmltate min. swell M100 Mano Ta EB ness at 70 C.

EXAMPLE4 TABLE VII v I M Maximum Compound extrusion Percent viscosity, 1 rate, i't./ e ML 10 at This example illustrates the effect of a variety of mterfa- Amount of sorbltan monopalmitate min. swell 212' F. cially active compounds. The procedure is the same as fol- 3 43 43 85 lowed in example 1 except EPH Copolymer B is used and a 33 44 88 rubber" screw is employed in the extruder. The stocks are 6 g2 g; cured for minutes at 32 0 F. A 7 a a TABLE V.EXTRUSION AND VULCANIZATE CHARACTERISTICS Interfaeially active material Maximum Percent Compression extrusion die Perm. set set B," 22 Shore A Amount Type ft lratie, swell M Mam Tn E- at break hrs/70 C. hardness 0 44 39 320 645 2, 185 795 108 62. 5 ROS01Na 49 250' 535 1,950 590 so an 56 Sorbitan monopalmitate 56 290 640 2, 625 72 I 37 61 3 ArSOaNa 49 300 660 2, 315 670 84 32 58, 5 3 R(|?N(CH:CH:OH): 76 50 295 635 2,315 695 87 40 61.5

1.5 RN+(CHa)aCl 82 58 265 550 2,470 700 84 37 59.5

I Where R is dodecyl. b Where Ar is dodecylphenyl. s Where R is undecyl. Where R is eetadecyl.

TABLE VI Vulcanlzate properties Maximum extrusion Compression rate, Die Shore A Set "B," Addition point It./inin. swell M M TB E hardness 22 hrs./70 C 46 44 290 590 1, 740 830 59 56 p itate 65 66 250 465 1,820 725 56 41 3 RN+(CHa)3Cl- 73 68 285 535 2,150 790 59 47 (h) CHzCHzOH 3 RCN ...-d0 69 79 300 565 2,075 730 61 43 CHzCHzOH 3 Sorbitan monopalmitate e. To clay 61 65 250 464 1,900 740 53 42 3 RN (CH:i)aC1- d0 75 67 285 550 2,000 750 58 47 O CI'IiiCHzOH 3 R-( ]N ..do 75 78 285 565 2,100 756 59 42 CHzCH 0H I R is octadeeyl. Ris undecyl. H Mn, Mi, ...7 m

TABLE VIII.VULCANIZATE DATA Cure, 320 F./15 min. Cure, 320 F./3O min. Compression Amount of sorbltan Permanent Permanent Shore A Set B 22 monopalmitate M100 M300 TB B set M M '1); a set hardness hrs/70 0. 225 225 420 107 200 32-5 380 520 109 55 65 350 525 700 137 275 490 1, 100 780 124 49 53 320 910 880 137 250 425 1,350 785 103 54 53 340 1,350 800 98 220 440 1,625 715 81 51 50 EXAMPLE 7 10 d. alkali metal or ammonium phosphonates, the anion of w w r i nd Ethylene-propylene-hexadiene Tripolymer C Is com- 6 g gz za sga 222 t ahenol pounded in the following formulation: m u o y p y p monosulfate, sodium oleyl p-anisldme sulfonate, lauryl picolinium p-toluene sulfonate, the sodium salt of sul- Polymer l00 zinc oxide 5 fonated propyl oleate, monobutyl biphenyl sodium HAF Black monosulfate and the sodium salt of sulfated propyl Ag ii R n 0 2 y i e -t t y l2- oleate; wherein the ammonium ions of the anionic surd'hydmlmmmel factants described above have the formula BIS(G,lI*d|Bm(hy|- 7 A V V "mm" benzyhperoxide I0 20 (40% active in- Q\ gredient supported Q1 H on precipitated calcium carbonate) H TABLE IX.-EXTRUSION DATA Max. Min. rat rate, Amount of sorbitan Feed charac- Extrudato in./ in./ Extrudate monopalmitate teristics surface min. min. temp. F.

Erratic Rough 68 28 255 Good Smooth. 74 68 240 TABLE X.VULCANIZATE DATA (6 MIN. AT 370 F.)

' After 70 Compression hrs/302 F. Amount of sorbitan Hardset, 22 hrs./ monopalmitate M '1 EB ness 302 F. TB

What is claimed is:

l. A filler-loaded elastomer consisting essentially of in parts by weight (a) an elastomeric copolymer of at least one amonoolefin and at least one nonconjugated hydrocarbon diene, said copolymer having about 0.1-2.0 gram-moles of ethylenic unsaturation per kilogram of copolymer; (b) about 20-300 parts per 100 parts of copolymer of a clay or carbonblack filler, with the proviso that when the filler is carbon black, there is not more than about 150 parts of filler; and (c) about 0.1-6.0 parts per 100 parts of copolymer of an interfacially active compound from the group consisting of l. cationic surfactants of the formula wherein R is an alkyl, alkaryl or aralkyl group containing about eight to 22 carbon atoms, R, R, individually are C C, alkyl or are joined together to form a 5 or 6 membered aliphatic or aromatic ring consisting of carbon atoms and not more than two hetero atoms, including the nitrogen atom shown, from the group of nitrogen and oxygen, R is C,-C, alkyl or benzyl, and X is halide, nitrate, menthanosulfate (CH OSO )BY- or ethanosulfate (Cl-l CH OSO 2. anionic surfactants which are:

a. alkali metal or ammonium sulfates, the sulfate anion of which has the formula: R 080; wherein R is C -C alkyl or C -C alkenyl;

alkali metal or ammonium sulfonates, the anion of which has the formula R 50 wherein R is a C -C alkyl,

C -C alkaryl, or C -C aralkyl, wherein the aryl groups have six to 15 carbon atoms; 15 c. alkali metal or ammonium phosphates, the anion of which has the formula R OPO wherein R =R wherein Q, Q; and 0 are independently hydrogen, methyl, ethyl or hydroxy ethyl;

3. nonionic surfactants of the formula wherein R is C -C alkyl, alkaryl, alkenyl or aralkyl and Y and Y are individually hydrogen or a C,-C alkanol radical, with the proviso that not more than one of Y or Y' is hydrogen; and nonionic surfactants of the formula ii I aBPIQi Lh wherein R =R and Y is a monovalent radical derived from an aliphatic polyhydroxy compound having a molecular weight less than 250.

2. A composition of claim 1 wherein the filler is hard kaolin clay.

3. A composition of claim 1 wherein the copolymer is prepared from about 30-70 weight percent ethylene, 60-20 weight percent propylene, and up to about 10 weight percent 1 ,4-hexadiene or S-ethylidene-Z-norbornene.

4. A composition of claim 3 wherein the dieneis l,4-hexadiene.

5. A composition of claim 1 wherein the surfactant is sor- I bitan monopalmitate, lauric diethanolamide or stearyl trimethylammonium chloride.

6. A composition of claim 1 wherein the surfactant is sorbitan monopalmitate.

7. A composition of claim 1 wherein the filler is a hard kaolin clay present in the amount of about -120 parts by l3. l4, weight per 100 parts of copolymer; the copolymer consists es- 1 with sulfur. sentially of about 30-70 weight percent ethylene, about 60-20 10.. A vulcanizate prepared by curing a composition of weight percent propylene and up to about percent 1,4-hexclaim 6 with sulfur. adiene; and the surfactant is sorbitan monopalmitate. l 1. A vulcanizate prepared by curing a composition of a. A composition of claim 1 wherein the filler is carbon 5 claim 1 in which the filler is carbon black with a peroxide black present in the amount of about 30-80 parts by weight. A Vulcanilale P p y curing a composition 0f 9. A vulcanizate prepared by curing a composition of claim Flaim 7 with Sulfur- 

2. A composition of claim 1 wherein the filler is hard kaolin clay.
 2. anionic surfactants which are: a. alkali metal or ammonium sulfates, the sulfate anion of which has the formula: R4OSO3 wherein R4 is C8C20 alkyl or C8C20 alkenyl; b. alkali metal or ammonium sulfonates, the anion of which has the formula R5SO3 wherein R5 is a C8C20alkyl, C8C20 alkaryl, or C8C20 aralkyl, wherein the aryl groups have six to 15 carbon atoms; 15 c. alkali metal or ammonium phosphates, the anion of which has the formula R6OPO3 wherein R6R5; d. alkali metal or ammonium phosphonates, the anion of which has the formula R7PO3 wherein R7R5; and e. the ammonium salt of monoethyl phenyl phenol monosulfate, sodium oleyl p-anisidine sulfonate, lauryl picolinium p-toluene sulfonate, the sodium salt of sulfonated propyl oleate, monobutyl biphenyl sodium monosulfate and the sodium salt of sulfated propyl oleate; wherein the ammonium ions of the anionic surfactants described above have the formula wherein Q, Q1 and Q2 are independently hydrogen, methyl, ethyl or hydroxy ethyl;
 3. nonionic surfactants of the formula wherein R8 is C8C22 alkyl, alkaryl, alkenyl or aralkyl and Y and Y'' are individually hydrogen or a C1C4 alkanol radical, with the proviso that not more than one of Y or Y'' is hydrogen; and nonionic surfactants of the formula wherein R9R8 and Y1 is a monovalent radical derived from an aliphatic polyhydroxy compound having a molecular weight less than
 250. 3. A composition of claim 1 wherein the copolymer is prepared from about 30-70 weight percent ethylene, 60-20 weight percent propylene, and up to about 10 weight percent 1,4-hexadiene or 5-ethylidene-2-norbornene.
 4. A composition of claim 3 wherein the diene is 1,4-hexadiene.
 5. A composition of claim 1 wherein the surfactant is sorbitan monopalmitate, lauric diethanolamide or stearyl trimethylammonium chloride.
 6. A composition of claim 1 wherein the surfactant is sorbitan monopalmitate.
 7. A composition of claim 1 wherein the filler is a hard kaolin clay present in the amount of about 80-120 parts by weight per 100 parts of copolymer; the copolymer consists essentially of about 30-70 weight percent ethylene, about 60-20 weight percent propylene and up to about 10 percent 1,4-hexadiene; and the surfactant is sorbitan monopalmitate.
 8. A composition of claim 1 wherein the filler is carbon black present in the amount of about 30-80 parts by weight.
 9. A vulcanizate prepared by curing a composition of claim 1 with sulfur.
 10. A vulcanizate prepared by curing a composition of claim 6 with sulfur.
 11. A vulcanizate prepared by curing a composition of claim 1 in which the filler is carbon black with a peroxide.
 12. A vulcanizate prepared by curing a composition of claim 7 with sulfur. 